1. Field of the Invention
The present invention relates to an absorber which is utilized as means for storing ink for use of an ink jet recording apparatus that records by discharging ink, and also, to a container for ink jet recording liquid that uses such absorber. More particularly, the invention relates to an absorber using the fibrous material whose elongation percentage is made within a specific range. The invention also relates to an ink jet liquid container using such absorber.
2. Related Background Art
Conventionally, from the viewpoint of a better ink supply performance for the ink jet recording head, it has been generally practiced to arrange the structure of an ink tank for use of ink jet recording, for adjusting the pressure exerted on the ink which is stored in the ink tank. The pressure thus exerted is termed as the xe2x80x9cnegative pressurexe2x80x9d, because this pressure is to make the pressure at the discharge port unit negative against the atmospheric pressure.
As one of the easiest methods for generating such negative pressure, an ink absorber is arranged in the ink tank for the utilization of the capillary force created by the absorber. Particularly, urethane sponge or some other foaming material is used as the ink absorber in consideration of the ease in forming a porous structure having a single hole ratio that presents an excellent ink holding capability. However, the foaming material, such as the urethane sponge, has each of foaming cells separated individually through a membrane in the status of its manufacture as it is, which requires the additional process to remove the membrane to make the urethane sponge usable as the ink absorber. Also, due to the chemical stability and other properties provided for the foaming material itself, there is a fear that an eluted substance is created depending on the kinds of ink that may be used. For that matter, restriction is imposed upon the kind of ink to be used.
In recent years, for the solution of the problems discussed above, it has been proposed to structure the ink absorber with a thermally fused felt which is one of fibrous materials as disclosed in the specification of Japanese Patent Laid-Open Application No. 07-323566.
Nevertheless, the ink absorber formed by thermally fused fibers as disclosed in the specification of the aforesaid patent laid-open application may present considerable changes in the dimension of the outer configuration of the absorber before and after the heat treatment to fuse the fibers themselves by the application of heat. In other words, the contouring dimension of the ink absorber is greatly shrunken after the execution of the heat treatment. If the ink absorber thus shrunken is inserted into the ink tank for use, the dimension of the ink absorber becomes smaller than the inner dimension of the ink tank to make it easier for the ink absorber to move in the ink tank. Then, if, for example, the ink tank is given a shock or the like, the ink absorber is displaced (to shift) in the ink tank to place the ink absorber away from the ink supply port of the ink jet head. As a result, the ink supply performance of the ink jet head is significantly lowered in some cases. Also, if the ink absorber is formed by laminating at least two kinds or more of fibrous blocks, there is a possibility that gaps are formed between the fibrous blocks of the ink absorber after the execution of the heat treatment in some cases. Then, ink is not allowed to move smoothly between the fibrous blocks due to the gaps thus formed, besides those problems discussed above. Therefore, the amount of remaining ink is increased in the ink absorber or the ink supply performance of the ink jet head is remarkably lowered in some cases. Moreover, the ink, which cannot be retained by the ink absorber, tends to reside in the space between the fibrous blocks, and there is a fear that ink leaks out from the ink tank when it is affected by the environmental (atmospheric pressure) changes or shocks that may take place.
The present invention is designed in consideration of the problems discussed above. It is an object of the invention to provide a thermally fused fibrous absorber which has a smaller heat shrinkage usable as an ink absorber capable of holding in stably and performing ink supply reliably, as well as to provide a container for storing ink jet recording liquid.
The inventors hereof have ardently studied and carried out experiments in order to achieve the aforesaid objectives. As a result, it is ascertained that the elongation percentage of the fiber, which should be used, exerts influences on the status of the absorber after having been thermally fused.
The present invention is based upon such knowledge, and it is characterized in that a fibrous absorber is formed by overlapping fibrous blocks at least a part of which is fused and bonded, and that the fiber that forms this absorber has the elongation percentage (Japanese Industrial Standard JIS-L1015, 1992 and/or 1994 edition) of 250% or less.
Here, it is preferable to satisfy the condition of 0.5 D (denier)xe2x89xa6Axe2x89xa610 D (denier) where the fineness of the fiber constituting the absorber is given as A. Also, it is preferable that given the fibrous length of the fiber constituting the absorber as L, the condition of 10 mmxe2x89xa6Lxe2x89xa6150 mm is satisfied.
Further, it may be possible to structure the absorber by laminating at least two or more fibrous blocks. Also, it is possible to use the absorber formed by polyolefin fibrous materials most suitably.
Also, in order to achieve the objectives described above, a container of the present invention for use of ink jet recording liquid is arranged to store recording liquid to be supplied to an ink jet recording head. This recording liquid container comprises the container main body, and an absorber holding recording liquid contained in the interior of the container main body, and the absorber is constituted by the fiber having its elongation percentage (Japanese Industrial Standard JIS-L1015) of 250% or less.
In this respect, it is preferable to satisfy the condition of 0.5 D (denier)xe2x89xa6Axe2x89xa610 D (denier) where the fineness of the fiber constituting the absorber is given as A. Also, it is preferable that given the fibrous length of the fiber constituting the absorber as L, the condition of 10 mmxe2x89xa6Lxe2x89xa6150 mm is satisfied.
Further, it may be possible to structure the absorber by laminating at least two or more fibrous blocks. Also, it is possible to use the absorber formed by polyolefine fibrous materials most suitably.
With the elongation percentage of the fibrous absorber manufactured by the thermal processing being defined within a specific range, it becomes possible to suppress the dimensional changes before and after the execution of the thermal processing, as well as to make the difference smaller between the higher and lower densities on the surface layer and the central portion of the fibrous absorber, respectively, hence providing a highly uniform absorber. Also, it becomes possible to avoid forming the gaps between fibers, thus providing the absorber that may present more stability with respect to the ink supply and holding performance thereof. Furthermore, even for the absorber of such a is type in which a plurality of fibrous blocks are laminated, it becomes possible to provide the absorber having no gaps created by the presence of boundaries that may be peeled off.
With the absorber described above, it is possible to manufacture an container for ink jet recording liquid having an excellent ink supply stability.